What is HLH reactive hemophagocytic syndrome?

Updated: Sep 16, 2020
  • Author: Cameron K Tebbi, MD; Chief Editor: Vikramjit S Kanwar, MBBS, MBA, MRCP(UK), FAAP  more...
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HLH reactive hemophagocytic syndrome

This is a reversible proliferation of histiocytes in response to viral, bacterial, fungal, and parasitic infections and autoimmune disorders, as well as secondary to various cancers. [60] This syndrome is most prevalent in individuals of Asian descent. [92] The disease may be a manifestation of impaired immune response to an infection or to secondary immunodeficiency, with many patients having defects in cellular cytotoxicity and immune deficiencies. [93]

Symptoms are often systemic and include fever and a viral-like illness. Patients frequently have a rash and an enlarged liver, spleen, and lymph nodes. Pancytopenia, increased liver enzyme levels, and an abnormal coagulation profile are common. Epstein-Barr virus is a common triggering organism.

Pathologically enlarged lymph nodes may have intact architecture with increased histiocytes in the sinusoids and paracortical areas. Histiocytes may exhibit platelet phagocytosis. Histiocytic hyperplasia may also be evident in the liver and spleen. The disease is usually self-limiting, but treatment with chemotherapy may be required when the disease is severe.

Instances of a combination of T-cell lymphoma with benign infiltration of histiocytes have been reported. [94, 95, 96] Upon histologic analysis, the process involves various types of malignant lymphomas, which are often of T-cell origin. Production of cytokines by lymphoma cells is suspected to cause phagocytosis. Upregulation of the TNF-alpha gene by Epstein-Barr virus and activation of macrophages by T cells infected with this virus, with interferon (INF) and other cytokine production, have been found. [97] Occurrence of LCH with various leukemias and solid tumors has also been reported. [98]

Lymphoma-associated hemophagocytic syndrome (LAHS) is a major subtype of the adult onset secondary HLH. This disorder often lacks mass formation and delayed enlargement of the lymph nodes. The ratio of serum soluble interleukin-2 receptor to ferritin has been shown to be useful as a marker in the diagnosis of LAHS. [99]

In some disorders, such as Kikuchi-Fujimoto disease (KFD) (histiocytic necrotizing lymphadenitis), which is a self-limiting disorder that affects cervical lymph nodes; hemophagocytic lymphohistiocytosis is seen. [100, 101]

Malignant T cells that express T-cell receptor gamma/delta have been found in adult and, rarely, pediatric patients with fever and hepatosplenomegaly. The red pulp of spleen and sinusoids of the liver contain large lymphoid cells with erythrophagocytosis. [102, 103, 104, 105]


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